A typical motion detection optical encoder has a light emitter, an encoder disk with a plurality of apertures and a light detector with photodetectors. In general, an optical encoder works by emitting a collimated light beam towards the encoder disk. The light beam is interrupted by the encoder disk as the encoder disk moves. Portions of the collimated light beam project through the apertures, onto the light detector. As the encoder disk moves, the light pattern falling on the photodiodes changes; hence corresponding output signals generated by the photodetectors also change accordingly. The photodetectors detect these light patterns to generate corresponding output signals, which can be processed to produce digital waveforms. Such digital waveforms of the output signals can be subsequently translated to motion information, for example, a position or a velocity of a motor.
An encoder system may be susceptible to light degradation. Brightness of the light emitter in the encoder system may deteriorate through time. Additionally, unwanted dust particles or contaminants, which may accumulate on the light emitter or the lens, may affect the brightness of the light emitter. Such a light degradation may subsequently cause current generated by the photodetector to become lower, hence lowering the performance of encoder electronics.
Therefore, what is needed is a simple and effective LED regulation system which may detect light degradation and also may regulate the LED current in the encoder system, which may substantially overcome such light degradation. What is also needed is a real time system and method for providing a real time LED current regulation to the encoder system.